Dataset Information

Evolution of Drug-resistant Acinetobacter baumannii After DCD Renal Transplantation.

ABSTRACT: Infection after renal transplantation remains a major cause of morbidity and death, especially infection from the extensively drug-resistant bacteria, A. baumannii. A total of fourteen A. baumannii isolates were isolated from the donors' preserved fluid from DCD (donation after cardiac death) renal transplantation and four isolates in the recipients' draining liquid at the Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, from March 2013 to November 2014. An outbreak of A. baumannii emerging after DCD renal transplantation was tracked to understand the transmission of the pathogen. PFGE displayed similar DNA patterns between isolates from the same hospital. Antimicrobial susceptibility tests against thirteen antimicrobial agents were determined using the K-B diffusion method and eTest. Whole-genome sequencing was applied to investigate the genetic relationship of the isolates. With the clinical data and research results, we concluded that the A. baumannii isolates 3R1 and 3R2 was probably transmitted from the donor who acquired the bacteria during his stay in the ICU, while isolate 4R1 was transmitted from 3R1 and 3R2 via medical manipulation. This study demonstrated the value of integration of clinical profiles with molecular methods in outbreak investigation and their importance in controlling infection and preventing serious complications after DCD transplantation.

SUBMITTER: Jiang H

PROVIDER: S-EPMC5434021 | biostudies-literature | 2017 May

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Evolution of Drug-resistant Acinetobacter baumannii After DCD Renal Transplantation.

Jiang Hong H Cao Luxi L Qu Lihui L Qu Tingting T Liu Guangjun G Wang Rending R Li Bingjue B Wang Yuchen Y Ying Chaoqun C Chen Miao M Lu Yingying Y Feng Shi S Xiao Yonghong Y Wang Junwen J Wu Jianyong J Chen Jianghua J

Scientific reports 20170516 1

Infection after renal transplantation remains a major cause of morbidity and death, especially infection from the extensively drug-resistant bacteria, A. baumannii. A total of fourteen A. baumannii isolates were isolated from the donors' preserved fluid from DCD (donation after cardiac death) renal transplantation and four isolates in the recipients' draining liquid at the Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, from March 2013 to November ...[more]

PMID: 28512290

Similar Datasets

Project description:Acinetobacter baumannii is a nosocomial agent with a high propensity for developing resistance to antibiotics. This ability relies on horizontal gene transfer mechanisms occurring in the Acinetobacter genus, including natural transformation. To study natural transformation in bacteria, the most prevalent method uses selection for the acquisition of an antibiotic resistance marker in a target chromosomal locus by the recipient cell. Most clinical isolates of A. baumannii are resistant to multiple antibiotics limiting the use of such selection-based method. Here we report the development of a phenotypic and selection-free method based on flow cytometry to detect transformation events in multidrug resistant (MDR) clinical A. baumannii isolates. To this end, we engineered a translational fusion between the abundant and conserved A. baumannii nucleoprotein (HU) and the superfolder green fluorescent protein (sfGFP). The new method was benchmarked against the conventional antibiotic selection-based method. Using this new method, we investigated several parameters affecting transformation efficiencies and identified conditions of transformability one hundred times higher than those previously reported. Using optimized transformation conditions, we probed natural transformation in a set of MDR clinical and non-clinical animal A. baumannii isolates. Regardless of their origin, the majority of the isolates displayed natural transformability, indicative of a conserved trait in the species. Overall, this new method and optimized protocol will greatly facilitate the study of natural transformation in the opportunistic pathogen A. baumanniiIMPORTANCE Antibiotic resistance is a pressing global health concern with the rise of multiple and pan-resistant pathogens. The rapid and unfailing resistance to multiple antibiotics of the nosocomial agent Acinetobacter baumannii, notably to carbapenems, prompt to understand the mechanisms behind acquisition of new antibiotic resistance genes. Natural transformation, one of horizontal gene transfer mechanisms in bacteria, was only recently described in A. baumannii and could explain its ability to acquire resistance genes. We developed a reliable method to probe and study natural transformation mechanism in A. baumannii More broadly, this new method based on flow cytometry will allow experimental detection and quantification of horizontal gene transfer events in multidrug resistant A. baumannii.

Project description:Nosocomial infections with Acinetobacter baumannii are a global problem in intensive care units with high mortality rates. Increasing resistance to first- and second-line antibiotics has forced the use of colistin as last-resort treatment, and increasing development of colistin resistance in A. baumannii has been reported. We evaluated the transcriptional regulator PmrA as potential drug target to restore colistin efficacy in A. baumannii Deletion of pmrA restored colistin susceptibility in 10 of the 12 extensively drug-resistant A. baumannii clinical isolates studied, indicating the importance of PmrA in the drug resistance phenotype. However, two strains remained highly resistant, indicating that PmrA-mediated overexpression of the phosphoethanolamine (PetN) transferase PmrC is not the exclusive colistin resistance mechanism in A. baumannii A detailed genetic characterization revealed a new colistin resistance mechanism mediated by genetic integration of the insertion element ISAbaI upstream of the PmrC homolog EptA (93% identity), leading to its overexpression. We found that eptA was ubiquitously present in clinical strains belonging to the international clone 2, and ISAbaI integration upstream of eptA was required to mediate the colistin-resistant phenotype. In addition, we found a duplicated ISAbaI-eptA cassette in one isolate, indicating that this colistin resistance determinant may be embedded in a mobile genetic element. Our data disprove PmrA as a drug target for adjuvant therapy but highlight the importance of PetN transferase-mediated colistin resistance in clinical strains. We suggest that direct targeting of the homologous PetN transferases PmrC/EptA may have the potential to overcome colistin resistance in A. baumanniiIMPORTANCE The discovery of antibiotics revolutionized modern medicine and enabled us to cure previously deadly bacterial infections. However, a progressive increase in antibiotic resistance rates is a major and global threat for our health care system. Colistin represents one of our last-resort antibiotics that is still active against most Gram-negative bacterial pathogens, but increasing resistance is reported worldwide, in particular due to the plasmid-encoded protein MCR-1 present in pathogens such as Escherichia coli and Klebsiella pneumoniae Here, we showed that colistin resistance in A. baumannii, a top-priority pathogen causing deadly nosocomial infections, is mediated through different avenues that result in increased activity of homologous phosphoethanolamine (PetN) transferases. Considering that MCR-1 is also a PetN transferase, our findings indicate that PetN transferases might be the Achilles heel of superbugs and that direct targeting of them may have the potential to preserve the activity of polymyxin antibiotics.

Project description:Acinetobacter baumannii is an important opportunistic pathogen of nosocomial infections. A. baumannii presently exhibits increasing antibiotic resistance, which poses great challenges to public health. The occurrence of tigecycline-resistant A. baumannii is related to tigecycline treatment and the within-host evolution of bacteria. We analyzed isogenic A. baumannii isolates from two critically ill patients who underwent tigecycline treatment. Whole-genome sequencing and comparative analyses were performed to determine the characteristics of genomic evolution. We conducted phenotypic studies, including in vitro antibiotic sensitivity tests, biofilm formation tests, growth curve determination, serum bactericidal determination, and Galleria mellonella lethality assays. In vivo emergent tigecycline resistance was observed after tigecycline treatment. After the withdrawal of tigecycline pressure, tigecycline-resistant isolates were not isolated from one patient. Four tigecycline-resistant isolates exhibited lower growth rates. The biofilm formation and virulence characteristics of tigecycline-resistant isolates were reasonably different between the two patients. A special phenotype appeared after tigecycline treatment in both patients, accompanied by reduced serum tolerance, enhanced biofilm formation ability, and reduced virulence of Galleria mellonella. Most of the genomic variation occurred after the tigecycline treatment, primarily involving transcription-, signal transduction-, translation-, ribosomal biogenesis-, and cell wall biogenesis-related genes. We determined that the genomic variations in baeR, wzc, aroQ, rluC, and adeS and acquisition of ISAba1 were associated with tigecycline resistance in vivo. Capsular polysaccharide-related genes, wzc, and itrA2, and aroQ, were the key genes related to the virulence evolution of A. baumannii within the host. IMPORTANCE Multidrug-resistant Acinetobacter baumannii poses a huge challenge to clinical treatment, and tigecycline is considered a last-line drug for the treatment of multidrug-resistant A. baumannii. However, the mechanism of tigecycline resistance in vivo has not been elucidated. This study analyzed the genomic and phenotypic evolution of tigecycline-resistant A. baumannii in two critically ill patients. In this study, after treatment with tigecycline, tigecycline-resistant A. baumannii emerged with higher fitness costs. After the withdrawal of tigecycline pressure, tigecycline-resistant isolates were not isolated from one patient. The in vivo and in vitro virulence of the isolates exhibited diametrically opposite results in the two patients. Genomic variations in baeR, wzc, aroQ, rluC, and adeS and acquisition of ISAba1 were associated with tigecycline resistance in vivo. The capsular polysaccharide-related genes, wzc, itrA2, and aroQ, were the key genes related to the virulence of A. baumannii in hosts. Our research provides a theoretical basis for elucidating the mechanism of tigecycline resistance and presents new clues for future surveillance and treatment of multidrug-resistant A. baumannii.

Dataset Information

Evolution of Drug-resistant Acinetobacter baumannii After DCD Renal Transplantation.

Publications

Evolution of Drug-resistant Acinetobacter baumannii After DCD Renal Transplantation.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets